# Crypto Hash Engine MCP > The Crypto Hash Engine MCP instantly calculates deterministic cryptographic hashes like SHA-256, HMAC, and MD5. It generates mathematically guaranteed signatures for API requests and webhooks without needing any complex code. If your agent needs to verify data integrity or sign a payload using a specific secret key, this tool handles the crypto math perfectly. ## Overview - **Category:** security - **Price:** Free - **Tags:** crypto, hash, hmac, sha256, signature ## Description When you connect this MCP through Vinkius, your AI client gains access to rock-solid cryptographic functions. You don't need to worry about whether the underlying language model can perform accurate mathematics; it simply passes the raw data and the algorithm type to our engine. This is critical when integrating with any major service—think payment processors or banking APIs—because they all require signed payloads for verification. Instead of having your agent guess at a hash, you ask it to use this MCP. It offloads the heavy lifting to a dedicated V8 environment, guaranteeing a 100% accurate result every single time. This means you can securely verify that incoming webhooks are legitimate or generate signatures for outgoing data with mathematical certainty. It's about building trust into your data pipeline. ## Tools ### hash_payload Generates a cryptographic hash (MD5, SHA-256, etc.) or HMAC signature using raw data and an optional secret key. ## Prompt Examples **Prompt:** ``` Generate a SHA-256 hash of this string: `user@example.com`. ``` **Response:** ``` Hash Generated: `b4c9a289323b21a01c3e940f150eb9b8c542587f1abfd8f0e1cc1ffc5e475514` ``` **Prompt:** ``` Sign this Stripe webhook payload using HMAC-SHA256 with the secret `whsec_123`. ``` **Response:** ``` Signed Payload: Returned exact hex digest. ``` **Prompt:** ``` Create an MD5 checksum for this file content string. ``` **Response:** ``` MD5 Checksum: Computed successfully. ``` ## Capabilities ### Calculate standardized cryptographic hashes Generates standard digests (MD5, SHA-256, etc.) from raw text or payloads. ### Verify webhook authenticity using HMAC Signs and verifies webhooks by accepting a shared secret key to validate payload origins. ### Support multiple hashing algorithms Calculates hashes using MD5, SHA-1, SHA-256, or SHA-512 depending on the required standard. ## Use Cases ### Verifying a Stripe Payment Webhook A user receives a webhook notification from Stripe saying an invoice paid. Instead of blindly trusting it, they ask their agent to use `hash_payload` with the raw payload and the shared secret key. The resulting signature confirms the payment event is real before proceeding. ### Checking File Upload Integrity A system processes a large document upload. Before committing it to the database, the agent uses `hash_payload` with SHA-256 on the file's binary content. This guarantees that no data was corrupted or modified during transmission. ### Building an Audit Trail When a user changes their profile settings, the agent hashes the entire payload (username + email + timestamp) using SHA-512 and stores the hash. This provides an unchangeable proof of what data existed at that exact moment. ### Cross-Platform API Communication Two separate services need to talk, but neither trusts the other's network layer. They exchange a simple message and use `hash_payload` with HMAC signing on both ends. The receiving service validates the hash against its copy of the secret key. ## Benefits - Verification of Webhooks: Use the `hash_payload` tool to securely sign and verify incoming webhooks, ensuring that payment updates or status changes came from a legitimate source. This is mandatory for high-stakes integrations. - Data Integrity Proofing: Generate repeatable hashes for any data point (like user IDs or document content). If even one character changes, the hash fails, letting you know immediately something was tampered with. - Algorithm Flexibility: You don't get stuck on one standard. `hash_payload` supports MD5, SHA-1, SHA-256, and SHA-512, so it works whether a legacy system or a modern service requires the hash type. - Reliable Signatures: Stop relying on general AI reasoning for crypto math. This MCP uses native code to guarantee 100% accurate HMAC signatures when you provide the shared secret key. - Simplified Deployment: You get reliable, battle-tested crypto functions without writing boilerplate Node.js or Python hashing libraries into your agent's workflow. ## How It Works The bottom line is that your agent gets back an accurate, verifiable signature that proves the data hasn't changed since it was signed. 1. Tell your agent to use this MCP, providing the raw data payload and specifying the desired cryptographic algorithm (e.g., SHA-256). 2. If signing a webhook, you must also provide the shared secret key used by the source platform. 3. The engine executes the calculation deterministically and returns the exact hexadecimal hash string. ## Frequently Asked Questions **How do I use the Crypto Hash Engine MCP to verify a webhook signature?** You use `hash_payload` by providing the full raw payload of the webhook and, critically, supplying the shared secret key. The tool returns a calculated hash that must match the one sent in the header to prove authenticity. **Can I generate an MD5 hash with the Crypto Hash Engine MCP?** Yes. `hash_payload` accepts 'md5' as an algorithm parameter, allowing you to compute this older checksum type when required for legacy systems or basic integrity checks. **What if I forget the secret key when using hash_payload?** If you are performing HMAC signing (like with a webhook), omitting the secret key will result in an invalid signature, because that key is required to prove ownership of the data. **Does the Crypto Hash Engine MCP handle all types of hashing?** It handles standard cryptographic hashes including SHA-256 and SHA-512, which are best practice for modern security applications. You specify the exact algorithm needed in `hash_payload`. **When should I use a modern algorithm like SHA-256 instead of MD5 with hash_payload?** You should always prefer SHA-256 for any new implementation. While MD5 works, it is considered cryptographically weak and shouldn't be used when data security or integrity are critical. **Does the hash_payload tool guarantee that the signature will always be deterministic?** Yes, it guarantees mathematical certainty. Since this MCP utilizes Node's native crypto library, the resulting hash remains constant for the exact same input payload and secret key every time. **What types of data can I pass to hash_payload for signing?** You can pass raw strings, JSON payloads, or file content represented as plain text. The MCP treats all inputs purely as a sequence of bytes, ensuring the integrity check works regardless of source format. **Can I use hash_payload to sign webhooks coming from different sources?** Absolutely. As long as you provide the raw payload and the shared secret key, this MCP will deterministically generate the required HMAC signature for webhook verification, regardless of where it originated. **What algorithms are supported?** MD5, SHA-1, SHA-256, and SHA-512. **Can it do HMAC signing?** Yes, just provide the `secret` parameter and it will generate the HMAC variant. **Is the secret stored anywhere?** Absolutely not. The hashing occurs in real-time in memory and the secret is immediately discarded.